Control apparatus



Filed Jan. 14; 1939 2 Sheets-She et 1 FIG? /N VENTOR By R.G/LL/$ A TTORNEV May 4, 1943. R, w 2,318,479

CONTROL APPARATUS Filed bah. 14, 19:59 2 sheets-sheet 2 30 FIG. 5

- smfwm Wl/EA/TOR y R. G/LL/S Patented May 4, 1943 CONTROL APPARATUS Application January 14, 1939, Serial No. 250,977

(Cl. l36-4) 8 Claims.

This invention relates to control apparatus, and more particularly to thermocouple apparatus for controlling the temperature of heated material enclosed in a wall and while under pressure.

In the manufacture of electrical conductor cables it is frequently desirable to provide such a cable with a seamless sheath of lead, lead alley, or other suitable material. In many cases this is done by passing a cable core or cable through a suitable die mounted in the die block of an extrusion press so that the sheath is formed by the action of the press, about the core or cable as the latter passes through the die. Such a 1 press ordinarily has an extrusion cylinder to composition of the material and also perhaps with the dimensions and thickness of the cable and sheath. This optimum temperature will however, in general, be constant for any one set of such conditions. It is therefore important to be able to know the temperature of the material in the cylinder at any time during the process. However, considering that the cylinder of such a press is necessarily a massive piece of steel and that the material contained in it is under relatively enormous pressures (which in the case of a lead sheathing press may be of the order of 55,000 lbs. per square inch), so that the material behaves in some ways like a fluid, transmitting the pressure in .all directions, it is not practicable to introduce any temperature reporting instrument into the body of the material itself, and extreme care must be taken as to the sealing of any openings in the wall of the cylinder itself and as to the structure of an instrument exposed directly to such pressure.

' An object of the present invention is to provide s mple, accurate, reliable and safe means to report the temperature of heated material in a container and under pressure.

With the above and other objects in view, one

embodiment of the invention may comprise a generally rod-shaped thermocouple or analogous device, housed in a tube of metal constructed to be mounted in a suitable bore in the wall of a container, the temperature sensitive end of the thermocouple being supported in a body ofiheat insulating material to separate the thermocouple from the tube and to close the end of the tube while exposing the tip of the thermocouple either nakedly or through a heat conductive metal shield to material in the container.

Other objects and features of the invention will appear from the following detailed. description of one embodiment thereof in a temperature responsive device intended tobe mounted in the wall of 'the cylinder of a lead cable sheathing press, taken in connection with the accompanying drawings in'which the same reference numerals are applied to identical parts in the several figures and in which Fig. 1 is a partial view in front elevation of a lead cable sheathing press having therein a temperature reporting device constructed in accordance with the invention;

Fig. 2 is a view partlyin section on the line 2-2 of Fig. 1; i 1

Fig. 3 is an enlarged detached end view partly in section of the device; 1

Fig. 4 is a section on the line 4-4 of Fig. 3;

Fig. 5 is a section on the line 5-5 of Fig. 4;

Fig. 6 is a fragmentary view, similar to a par of Fig.4, of a modified form;

Fig. 7 is a view corresponding to Fig. 3 of a second modified form; and

Fig. 8 is a section on the line 8-8101 Fig. 7.

In the present disclosure, so much of a lead cable sheathingpress is shown in Figs. land 2 as is necessary toan understanding of the inven"- tion proper. Such a pressincludes-as a principal member of, its organization a hollow cylin'der 20 into which molten-leadis poured from above. The";lead is allowed to cool to-a temperature of the order of 350 400 F.,yat which it setsptor'a solid or nearly solid condition. A' ram is then introduced and forced down, causing the lead to be forced through an opening in the bottom of the cylinder into a chamberwhence it is extruded through a die mounted in the chamber wall. The pressure in the cylinder required to effect this will be of the order of 55,000 lbs. per square inch.

To be able to determine the temperature of the lead in the cylinder at any time, the device shown in Figs. 3, 4 and 5 is mounted in an appropriate bore 2| formed in the Wall 'of the cylinder, preferably radially and extending through the wall. As shown in Figs..1, 2 and 3; the device has a tubular housing 30 of steel or other suitable material fitting closely into the bore 2| throughout most of its length and locked into place in the bore by a screw thread 3| on the outer portion of the tube. A combined head and housing 32 is mounted on the tube 39, on the extreme outer end as shown, and is rigidly locked to the tube by means of one or more key screws 33. The outside of the member 32 is formed as a hexagonal bolt head and thus the member may serve as a head for the screw 3| when the tube is being seated in or removed from the bore 2|. A heavy nut 34 is threaded on the thread 3| outside of the head 32 and a spacing washer is placed loosely around the tube 30 inside of the nut 34.

Under the heavy pressure of operation of the press, a certain amount of lead will sometimes be forced, more or less far, as a film between the walls of the tube 33 and of the bore 2|, making it difiicult to withdraw the tube after the thread 3| has been retired out of engagement with the corresponding thread of the bore. nut 34 is provided to act as an extractor to complete the withdrawal of the tube. The washer 35 is provided and is interchangeable for others of different thicknesses to permit of placing the device in cylinders having walls of different thicknesses.

A thermocouple 36 consisting of an outer closed ended tube 31 and an inner coaxial rod or wire 38 welded together at 39 where the inner end of the rod rests against the end wall of the tube, is housed coaxially in the tube 33 and out of contact therewith throughout its length. The tube 31 and rod 38 are of dissimilar metals, as is customary in a thermocouple, one, for example, being of iron and the other of the 60% copper-40% nickel alloy known as constantan. The inner tip (the heat responsive or fhot juncture) of the thermocouple is flush with the inner end of the tube 30 and thus is exposed directly, when the tube 30 is in place in the bore 2|, to contact with the contents of the press cylinder 23. The inner end of the couple is both supported in and insulated fromthe tube 3|) by a centrally bored cylindrical plug 4|] of some suitable heat insulating material such as the hard burned porcelain known as lavite, which also serves to close the end of the tube 30 and is preferably secured in place with pins 4| and backed by a steel supporting ring 42 seated against a corresponding shoulder in the inside wall of the tube 30.

Preferably the tube 31 is spaced from the tube 30 throughout the rest of the distance from the ring 42 to the housing 32 by means of a helical coil of steel wire 43. with the tube 30 on one side and with the tube 31 on the other are both line contacts and the transfer of heat through the wire from one tube to the other is negligible.

The outer end of the tube 30 is closed by a plug 44 of steel or other suitable material, axially bored to receive and radially support the outer end of the tube 31. The bore of this plug is a three-lobed aperture, as shown, so that the contact of the tube 31 with the plug 44 is only along a line at the end of each of the radially inwardly projecting lugs which separate the lobes of the aperture. The outer extremity of the tube 31 abuts against and is longitudinally supported by a steel member 45 held in place by the housing lid 46 and the bolts'or screws 33. The electrical conductors 41 and 48 respectively attached to the tube 31 and rod 38 are brought out, preferably through a side wall of the housing 32, by any suitable means, and pass through the mem- The 13% The contact of this wire ber 45 by means of a central hole or a radial slot therein.

In case the pressure at the inner end of the device is too great to be born by the tip of the thermocouple 35, the structure may be modified as shown in Fig. 6. Here a protective member or plug 43, of highly heat conductive material, such as copper, is set into the lavite plug 43 to close the end of the bore therein, and the tip of the thermocouple is seated in an axial recess in the plug 43. The ring 42 is replaced by a lavite ring I42 and a flange on the open end of the plug 49 is held between the ring I42 and the plug 43 to prevent the plug 43 from being displaced in either direction.

Another modified form is disclosed in Figs. '1 and 3. Here the structure of Figs. 4 and 6 is generally adapted to permit of the use of another type of thermocouple. In this case the thermocouple consists of two parallel wires or rods I31 and i352 of dissimilar metals, held out of contact with each other and with the walls of the tube 3|] by doubly perforated beads, or analogous members, I43, of electrical and heat insulating material such as lavite. The tips of these wires are threaded through parallel bores in the lavite plug 242, brought together, welded together, and soldered to the copper plug 49 at I39.

In the structure of Fig; 4, the tip of the thermocouple 36 is positioned to be flush with the inner ends of the plug 40 and of the tube 33 so that there will be no recess or chamber at the inner end of the device into which any appreciable amount of the cylinder contents can be lodged. Hence the thermocouple is always exposed to the flowing and changing contents of the cylinder and is not shielded by a fraction of the contents of a different temperature state than the main body. The same efi'ect, substantially is achieved in Figs. 6 and 8 by making the end faces of the plug 49, the plug 43 and the tube 30 mutually flush. Needless to say that when the device is seated in the bore 2| its inner end should be substantially flush with the cylinder wall, for the same reason.

The embodiments of the invention above disclosed are illustrated and may be modified and departed from in various ways without departing from the spirit and scope of the invention as pointed out in and limited only by the appended claims.

What is claimed is:

1. A device for reporting the temperature state of material in a container, comprising a tubular metal housing to extend through and seal an aperture in a container wall, temperature responsive means housed Within the housing and having a temperature sensitive element at the inner end of the housing to be affected by the temperature state of material in the container, and a rigid sleeve of hard insulating material between the element and the housingbut not covering the tip of the element, to render the inner end of the device fiush across and prevent deposit of material therein.

2. A device for reporting the temperature state of material in a container, comprising a tubular metal housing to extend through and seal an aperture in a container wall, temperature responsive means housed within the housing and having a temperature sensitive element at the inner end of the housing and flush therewith and uncovered thereby to be affected by the temperature state of material in the container, and a rigid sleeve of hard insulating material between the element and the housing but not covering the tip of the element, to render the inner end of the device flush across and prevent deposit of material therein.

3. A device for reporting the temperature state of material in a container, comprising a tubular metal housing to extend through and seal an aperture in a container wall, a thermocouple housed within the housing and having the juncture of the thermocouple at the inner end of the housing to be affected by the temperature state of material in the container, and a rigid sleeve of hard insulating material between the juncture and the housing but not covering the tip of the juncture, to render the inner end of the device flush across and prevent deposit of material therein under pressure.

4. A device for reporting the temperature state of material in a container, comprising a tubular metal housing to extend through and seal an aperture in a container wall, a thermocouple housed within the housing and having the juncture of the thermocouple at the inner end of the housing and flush therewith and uncovered thereby to be affected by the temperature state of material in the container, and a rigid sleeve of hard insulating material between the juncture and the housing but not covering the tip of the juncture, to render the inner end of the device flush across and prevent deposit of material therein under pressure.

5. A device for reporting the temperature state of material in a container, comprising a tubular housing to extend through and seal an aperture in a container wall, a thermocouple housed within the housing and having a guard of highly heat conductive material positioned on the juncture thereof and having the guard positioned at the inner end of the housing to be afiected by the temperature state of material in the container,

and a rigid sleeve of hard insulating material between the guard and the housing to render the inner end of the device flush across and prevent deposit of material therein under pressure.

6. A device for reporting the temperature state of material in a container, comprising a tubular housing to extend through and seal an aperture in a container wall, a thermocouple housed within the housing and having a guard of highly heat conductive material positioned on the juncture thereof and having the guard positioned at the inner end of the housing and flush therewith and uncovered thereby to be afiected by the tempera ture state of material in the container, and a rigid sleeve of hard insulating material between the guard and the housing to render the inner end of the device flush across and prevent deposit of material therein under pressure.

7. A device for reporting the temperature state of material in a container, comprising a tubular metal housing to extend through and seal an aperture in a container wall, a rod-shaped thermocouple unit within the housing and having its temperature sensitive junction at the inner end of the housing to be affected by the temperature state of material in the container, and a rigid sleeve of hard insulating material between the temperature sensitive junction and the housing but not covering the tip of the junction, to render the inner end of the device flush across and prevent deposit of material therein under pressure.

8. A device for reporting the temperature state of material in a container, comprising a tubular metal housing to extend through and seal an aperture in a container wall and having an open inner end, a rod-shaped thermocouple unit within the housing and having its temperature sensitive junction at the open inner end of the housing to be effected by the temperature state of material in the container, and a rigid sleeve of hard insulating material between the temperature sensitive junction and the housing but not covering the tip of the junction, to render the inner end of the device flush across and prevent deposit of material therein under pressure.

RANDALL GILLIS. 

